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A. L. KULICK. SPARK PLUG.-

APPLICATION FlLEDYlULY 26,1919.

Patented Mayr. 9,`1920.

.ANDREW L. KULICK, 0F DETROIT, MICHIGAN.

SPARK-PLUG.

Specification of Letters Patent.

Patented Mar. 9, 1920.

Application filed July 26, 1919. Serial No. 313,606.

To all whom t may concern:

Be it known that I, ANDRW L. KULrcn, a citizen of the United States, residing at Detroit, county of Wayne, State o f Michigan, have invented a certain new and useful Improvement in Spark-Plugs, and declare the following to be a full, clear, and exact description of the same, such as will enable others skilled in the art to which it pertains to make and use the same, reference being had to the accompanying drawings, which form a part of this specication.

My invention relates to an improvement in spark plugs, the object of which is to provide a spark plug simple in construction and inexpensive to build and so easily disassembled that without removing the plug in the cylinder or stopping the engine the central electrode may be withdrawn and cleaned and then reinserted in place.

In the drawings:

Figure l is a longitudinal sectional view of my improved plug assembled.,

Fig. 2 shows a modification wherein the porcelain insulating core is formed of lateral halves with recessed tubular ends.

Fig. 8 is a detail view of the central electrode and insulating cap formed thereon.

Fig. 4 is a longitudinal section on the insulating core b shown in Fig. l.

Fig. 5 is a sectional view of one of the halves of the core shown in Fig. 2.

Fig. 6 is a detail of the central electrode and insulating cap used in the modification as shown'in' Fig. 2.

Fig. 7 is a view of one of the modified insulating cores.

Similar letters refer to similar parts.

a and a2 are male and female members of a metallic shell, said metallic shell being eXteriorly threaded at each end to receive insulating cap e hereinafter referred to orto be screwed into the engine casing. b is the insulating core provided with a central longitudinal passageway b. This insulating core may be glazed inside as well as out as the central electrode is not fastened or cemented therein but merely passed therethrough. This core is formed as here shown with an enlarged central portion and reduced end portions. 0 represents a suitable gasket about which there is no novelty. d and cl2 are ground terminals of the outer electrode of the metallic shell located at opposite ends thereof. e is an insulating cap, bakelite is suggested but no claim is made to that material. f is the central electrode. Insulating cap e is molded or permanently secured to the central electrode f, said electrode being threaded or otherwise roughened the better to hold to the insulating material. g is a coller on the central electrode adapted to be received and seated in a slight depression in the lower extremity of the projecting sleeve e2. Insulating cap c is internally threaded so as to be screwe-d onto either end of the metallic shell. It is likewise provided with an internally projecting sleeve e2 surrounding central electrode and insulating the same from the external electrode. Below the collar g and between said collar and flattened end of the insulating core is a gasket It of suitable material to withstand heat, and act as a non-conductor of electricity to form a gas tight joint when said electrode is passed through the central opening'of said insulating core and the insulating cap is screwed down. j represents a lock nut and 7c is the terminal plug screwed on the eXterior proje.ting end of the electrode The feed wire to the electrode is not shown but its method of attachment is a conventional one and there is no novelty therein.

Fig. 2 is a modification. The insulating core is cylindrically recessed at its outer reduced ends and provided with al central cylindrical longitudinal passageway through which the central elect-rode may be passed. Insulating core may be formed in halves as shown in Fig. 5 or in one piece as in Fig. 7. Central eletrode f is carried by insulating cap e in ai manner similar to that shown in Fig. l. Lock nut j and terminal plug 7c are not shown, neither is the line wire from the electrical circuit. The insulating cap e in this modification, however, is provided with a substantially longer internally projecting sleeve e3 than is found in Fig. l. This sleeve surrounds and is formed to the elect-rode in a manner similar to that 0f the the electrode is firmly seated in the recessed end of the cap sleeve and a gas tight joint formed between said collar and the porcelain through the gasket.

It will be noted from the above that the spark plug here provided may be disassembled by unscrewing insulating cap c and withdrawing such insulating cap carrying with it the central electrode. This mary be done while the engine is running and without removing the plug from the engine.

In the case of collection of carbon or foul material on electrode f or its ground terminal or upon the porcelain insulating core the withdrawal of the central electrode will break any carbon connection formed with the ground terminal and the deposit on the electrode will be cleaned ofi1 as the same is withdrawn from the porcelain core. If the engine is left ruiming a blast of gas forced through longitudinal opening b of the 1nsulating core will ordinarily wash out the saine. Should the plug be so fouled that it fails to operate after cleaning as above, it may be removed. from the engine and reversed end for end. In the modification shown in Fig. 2, insulating core may be composed of halves b2 and b3 cylindrically recessed at their reduced outer ends, as shown, to receive internally projecting cylindrical sleeve e3 of the insulating cap c.

As will be seen, the extent of carbonization necessary in this modification for a short circuit would be very nearly impossible of attainment. The central electrode could be withdrawn in the manner described above in Fig. l. In addition, in case of a break in one end of the porcelain core the plug might be withdrawn from the engine and by reversing the position of the insulating halves a working plug would be the result.

This plug because of the fact that it'can be cleaned Vwithout removing from the engine andwhile the engine is running would be particularly adaptable for airplane engine work.

Protected as the insulating core is by the use of a metallic shell, this plug would be peculiarly adaptable to marine work.

Expansion of the central electrode due to heating would tend to tighten the gas joint between the gasket z, and the llattened end of the core b. rather than to open up the same.`

l/Vhat I claimvis:

'1. In a spark plug. the combination with a metallic shell provided with a ground terminal at either endexternally threaded at each end, of an insulating core provided with a fentral longitudinal passageway. an insulating cap internally threadedaidapted to be screwed on either end of said metallic shelhand a central electrode permanently carriedby said insulating cap and adapted to be` passed through ,thecentral opening in said insulating core.

2. In a spark plug, the .combination with a metallic shell formed of male and female halves externally threaded at their outer ends provided with ground terminals at said ends disposed in sparking proximity to a central electrode, of an insulating core carried by said shell, said insulating core formed with recessed outer ends and axial longitudinal passageway therethrough, an insulating ca=p internally threaded adapted to be screwed. on either en d of said metallic shell provided with a longitudinal internally projecting sleeve adapted to be disposed.within said tubular recess of said insulating core, a central electrode permanently axially embedded within said insulating cap and sleeve and` adapted tof'be passed through said longitudinal passageway ofsaid insulating core.

3. Ina spark plug, the combinatiOn with a metallic shell formed ofl male and female halves externally threaded at its outerends of ground terminals at eitherendthereof disposed in sparking proximity to a central electrode, an insulating core adapted tok be carried by said shell provided with a central longitudinal passageway therethrough, an insulating cap internally threaded and adapted to be screwedon either end of said metallic shell, the central electrode permanently carried by said insulating cap` one end thereof projecting above said cap and threaded to receive a lock nut and terminal plug connecting up the electric circuit feed wire, said insulating cap being provided with an axially disposed internally projecting sleeve surrounding said central electrode to where it enters insulating core and insulating it from the externalelectrode.

4. In a spark plug, the combination with a metallic shell formed ofmale and female halves externally vthreaded at their outer ends of ground terminals at either end thereof disposed in sparking proximity to the central electrode, an insulating core carried by said shell and providedwith a cylindrical central longitudinal passageway therethrough, aninsnlating cap adapted to be screwed on either end of saidshellprovided with an axial internally projecting `sleeve recessed at its lower extremity, a central electrode-disposed axially through said insulating cap and sleeve and permanently carried thereby provided with a collar formed thereon adapted to seat linsaid recessed end of said sleeve, a gasket surrounding said-electrode disposed between said collar and the vendfof the insulating core.

5. In a spark plug,vthe combination with ametallic shell formed of male and female halves externally-threaded at the4 outer ends and provided with va groundterminal at either end dsposedinsparking proximity to the central electrode of an insulating core carried by said shell seated in suitable gaskets, said insulating core provided with a central longitudinal passageway therethrough and reduced opposite end portions permitting clearance of said metallic shell, an insulating cap internally threaded adapted to be screwed on either end of said me tallic shell provided with an axial internally projecting sleeve recessed at its lower extremity, a central electrode formed and permanently carried within said insulating cap threaded or roughened as it passes therethrough to embed itself more lirmly in the insulating material provided with an externally projecting portion threaded and adapted to receive a lock nut and terminal plug for carrying a line wire, provided with a collar adapted to seat in the recessed lower extremity of said insulating cap sleeve, a gasket adapted to be disposed between said collar and said insulating core.

6. In a spark plug, the combination with a metallic shell formed of male and female halves externally threaded at their outer ends provided with ground terminals at said ends disposed in sparking proximity to a central electrode, of an insulating core formed of halves carried by said shell, said insulating core formed with recessed outer ends and an axial longitudinal passageway therethrough, an insulating cap internally threaded adapted to be screwed on either end of said metallic shell provided with a longitudinal internally projecting sleeve adapted to be disposed within said tubular recess of said insulating core, a central electrode permanently carried by and axially disposed within said insulating cap and sleeve and adapted to be passed through s aid longitudinal passageway of said insulating core.

7. In a spark plug, the combination of an insulating core provided with an axial longitudinal passageway therethrough, a screw cap provided with an axial internally projecting sleeve, a` central electrode adapted to be passed through said passageway 1 n said insulating core and permanently axially disposed in said screw cap and sleeve, a collar on said electrode, a gasket adapted to be interposed between said collar and the porcelain core and to be firmly seated when said screw cap is screwed on said spark plug.

8. In a spark plug, the combination with a metallic shell formed of male and -lemale halves externally threaded at opposite ends and provided with ground terminals disposed in sparking proximity to a central electrode of an insulating core composed of lateral halves with longitudinal tubular recessed ends reduced for clearance in said metallic shell, said insulating core provided with a longitudinal passageway therethrough, an insulating cap adapted to be screwed on either end of said metallic shell provided with an axially internally projecting sleeve adapted to be disposed within said tubular opening in said insulating core with a provided clearance therein, a central electrode permanently carried by said insulating cap adapted to pass through said longitudinal opening in said insulating core, a collar on said electrode adapted to be seated in a recess in thel lower extremity of said cap. sleeve, a gasket adapted to be interposed between said collar and the seat of said tubular recessed opening in said insulating c ore.

9. In a spark plug, the combination with a metallic shell formed of male and female halves externally threaded at their outer ends provided with ground terminals at their ends disposed in sparking proximity to a central electrode, of an insulating core provided with an axial longitudinal passageway therethrough terminating in enlarged cylindrical recesses at its ends, and an insulating cap provided with an axial internally projecting sleeve adapted to be disposed within said cylindrical recess, a central electrode embedded axially in said cap and sleeve and adapted to pass through the longitudinal passageway in said insulating core, a collar on said electrode seated in the lower end of said cap sleeve, a gasket adapted to be interposed between said collar and said insulating core and held firmly in place with the screwing of said insulating cap on the end of said shell.

10. In a spark plug, the combination with a metallic shell provided with a ground terminal adapted to receive a screw cap, of an insulating core composed of lateral halves provided with a longitudinal passageway therethrough terminating in cylindrical recesses and an insulating cap provided with an internally projecting sleeve, a central electrode axially permanently disposed within said cap and sleeve and adapted to pass through said longitudinal opening in said insulating core, said cap sleeve adapted to be seated in said tubular recess of said core, a collar on said electrode seated in the lower end of said cap sleeve, a gasket adapted to be interposed between said collar and the seat of said cylindrical recess forming a gas tight joint when said cap is screwed on the outer shell.

ll. In a spark plug, an outer shell provided with a ground terminal, an insulating core provided with a longitudinal passageway therethrough, an insulating cap carrying a central electrode adapted to be passed through said longitudinal passageway in said insulating core, a collar on said electrode, a gasket abutting said collar, said cap adapted to be screwed on said outer shell seating said gasket and electrode collar imlygairlst Sai-d. .insulating @reim-. the latngwap, a.; gasket adaptedf to. Surround forniatinff'a.gaSE-tight'jointi K Slfd "el'ctiode ffinflV fi'ni gas 'tight .joint l2. In al 'sprkplug an insulating core betweenthe' eXtgrnalndOfsaid insulating 10 .providedA With etl longitudinal pas'sageway core and said cap When the c zvalpvifs :screwedl on 5 adapted'to receive an electrode, an insulatsaidfplug. 4

ing'a'p adapted to be screwed on said sparking plug, an' electrode carried byrsaid insu- L. K'ULICVKLA 

